Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

Easiest disposal of CuCl2 solution.

Since you don't know how much HCl is left in the solution, the best thing to do is to use Sodium carbonate. It can be easily obtained from a pottery supply stores. Cheap. Ask a high school ceramic instructor on where to get it or ask any self respecting potter or ceramics artist. Cost is around $2-$4 per pound I think... You don't need much more than a pound for a very long time.

Pour sodium carbonate crystals into your "spent" solution. Excess sodium carbonate is fine. CuCl2 will react and precipitate out as Copper carbonate. Filter it out using coffee filter. Liquid should be excess sodium carbonate, regular table salt and water.

Dump the liquid down a drain.

Dump the Copper carbonate precipitate into trash.

If you really want to be safe!! You can reduce the copper carbonate in a furnace/kiln and heat the copper carbonate to around 200C. And it will turn black. You are decomposing the carbonate to release CO2 and what remains is Copper oxide. black powder. At this point its, very safe. But it can stain clothing.

Dumping Copper chloride solution into a bucket of wood chips makes more toxic waste, so stop it!!

Follow the directions on this post and all is well.

BTW, same procedure works for Ferric Chloride etchant. If it is used on Ferric chloride solution, I would decompose the precipitate in a furnace. to create iron oxide, (rust).